KR20060128448A - Light guide plate, backlight assembly and liquid crystal display device having same - Google Patents

Abstract

Disclosed are a light guide plate, a backlight assembly having the same, and a liquid crystal display device capable of improving luminance characteristics. The light guide plate includes a light incident part to which light from the lamp is incident, a light facing part having a thickness thinner than the light receiving part, a light emitting part extending vertically from an upper side of the light receiving part and connected to an upper side of the light receiving part, and a lower side of the light receiving part. It extends from and includes a reflecting portion connected to the lower side of the light portion. A plurality of first prism patterns are formed in the reflecting portion, and the first prism patterns are formed in parallel with the emission portion. Therefore, it is possible to reduce the lost light emitted to the side and to increase the brightness of the light emitted to the exit portion.

Description

LIGHT GUIDE PLATE, BACK LIGHT ASSEMBLY AND LIQUID CRYSTAL DISPLAY APPARATUS HAVING THE SAME}

1 is an exploded perspective view showing a backlight assembly according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of the light guide plate taken along line II ′ of FIG. 1.

3 is a plan view illustrating a reflection part of the light guide plate illustrated in FIG. 1.

4 is an enlarged view illustrating an enlarged portion A of FIG. 2.

5 is an enlarged view illustrating an enlarged portion B of FIG. 4.

FIG. 6 is a plan view illustrating another embodiment of the first prism patterns illustrated in FIG. 3.

FIG. 7 is a plan view illustrating still another embodiment of the first prism patterns illustrated in FIG. 3.

8 is a perspective view illustrating a light guide plate according to another exemplary embodiment of the present invention.

9 is an enlarged view illustrating an enlarged portion C of FIG. 8.

10 is an exploded perspective view illustrating a liquid crystal display according to an exemplary embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

100: backlight assembly 110: lamp

120: reflection sheet 200: light guide plate

210: light receiving unit 220: light receiving unit

230: emitting unit 240: reflecting unit

250: first prism pattern 252: first inclined surface

254: second inclined plane 256: third inclined plane

360: second prism pattern 400: liquid crystal display device

410: optical sheet 500: display unit

510: liquid crystal display panel 520: driving circuit

The present invention relates to a light guide plate, a backlight assembly having the same, and a liquid crystal display device. More particularly, the present invention relates to a light guide plate, a backlight assembly having the same, and a liquid crystal display device, which can reduce overall loss of light emitted from the side surface. will be.

In general, a liquid crystal display (LCD) is a display device that displays an image using a liquid crystal having optical and electrical characteristics such as anisotropic refractive index and anisotropic dielectric constant. Such liquid crystal displays are thinner and lighter than other display devices such as CRTs and PDPs, and have low driving voltages and low power consumption, and thus are widely used throughout the industry.

The liquid crystal display device includes a liquid crystal display panel including a thin film transistor (hereinafter, referred to as TFT) substrate, a color filter substrate facing the TFT substrate, and a liquid crystal layer interposed between the two substrates to change light transmittance. Liquid Crystal Display Panel).

In addition, since the liquid crystal display device is a non-light emitting device that does not emit light by itself, the liquid crystal display panel for displaying an image requires a backlight assembly for supplying light to the liquid crystal display panel.

The conventional backlight assembly includes a lamp for generating light and a light guide plate (LGP) for guiding a path of light incident from a lamp disposed on a side of the lamp toward a liquid crystal display panel.

The light guide plate is classified into a flat type having a light incident portion and a light facing portion opposite to the light incident portion having a same thickness, and a wedge type whose thickness decreases from the light incident portion toward the light facing portion.

Recently, in order to prevent discoloration of the light guide plate and to improve luminance, a prism light guide plate has been developed in which the light guide plate forms a prism pattern instead of a printing pattern on the lower surface.

In the case of a flat light guide plate having the same thickness, the light guided into the light guide plate always satisfies the total reflection condition, and thus is emitted vertically only by the prism pattern.

However, in the case of the wedge-shaped light guide plate, the light is not emitted only by the prism pattern due to the characteristics of the structure, and the light is emitted toward the light guide plate while not observing the total reflection condition while being guided into the light guide plate.

Accordingly, the present invention has been made in view of such a problem, and the present invention provides a light guide plate capable of reducing lost light emitted to the side and increasing luminance.

In addition, the present invention provides a backlight assembly having the light guide plate described above.

In addition, the present invention provides a liquid crystal display device having the above-described backlight assembly.

The light guide plate according to the above-described aspect of the present invention includes a light incident portion to which light from a lamp is incident, a light facing portion facing the light incident portion, and having a thickness smaller than that of the light incident portion, extending vertically from an upper side of the light incident portion. An emission part connected to an upper side of a part, and a reflecting part extending from a lower side of the light incident part and connected to a lower side of the light receiving part. A plurality of first prism patterns are formed in the reflective part, and the first prism patterns are formed in parallel with the emission part.

According to another aspect of the present invention, a light guide plate includes a light incident part to which light from a lamp is incident, a light facing part facing the light incident part, and having a thickness thinner than that of the light incident part, extending vertically from an upper side of the light incident part to an upper side of the light guide part. And a light emitting part connected to the light emitting part, and a reflecting part extending from a lower side of the light incident part and connected to a lower side of the light receiving part. A plurality of first prism patterns having a stripe shape parallel to the light incident part is formed in the reflecting part, and the first prism patterns are formed parallel to the output part. A plurality of second prism patterns are formed in the emission part in a direction perpendicular to the light incident part.

According to an aspect of the present invention, a backlight assembly includes a lamp for generating light, a light guide plate for guiding a path of light generated from the lamp, and a reflective sheet disposed below the light guide plate. The light guide plate may include a light incident part to which light from the lamp is incident, a light facing part having a thickness smaller than the light incident part, a light emitting part extending vertically from an upper side of the light incident part and connected to a top side of the light receiving part, And a reflection part extending from a lower side of the light incident part and connected to a lower side of the light incident part. A plurality of first prism patterns are formed in the reflective part, and the first prism patterns are formed in parallel with the emission part.

A liquid crystal display according to an aspect of the present invention includes a backlight assembly and a display unit. The backlight assembly includes a lamp for generating light, a light guide plate for guiding a path of light generated from the lamp, and a reflective sheet disposed below the light guide plate. The display unit has a liquid crystal display panel for displaying an image using light from the backlight assembly and a driving circuit unit for driving the liquid crystal display panel. The light guide plate may include a light incident part to which light from the lamp is incident, a light facing part having a thickness smaller than the light incident part, a light emitting part extending vertically from an upper side of the light incident part and connected to a top side of the light receiving part, And a reflection part extending from a lower side of the light incident part and connected to a lower side of the light incident part. A plurality of first prism patterns are formed in the reflective part, and the first prism patterns are formed in parallel with the emission part.

According to the light guide plate, the backlight assembly having the same, and the liquid crystal display device, the light guided into the light guide plate always meets the total reflection condition in the wedge-shaped light guide plate structure, thereby reducing the lost light emitted to the side and increasing the brightness of the light emitted to the exit part. You can.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is an exploded perspective view illustrating a backlight assembly according to an exemplary embodiment of the present invention, FIG. 2 is a cross-sectional view of a light guide plate taken along line II ′ of FIG. 1, and FIG. 3 is a reflection of the light guide plate illustrated in FIG. 1. It is a top view which showed the part.

1 to 3, the backlight assembly 100 according to an exemplary embodiment of the present invention may include a lamp 110 generating light, a light guide plate 200, and a light guide plate guiding a path of light generated from the lamp 110. The reflective sheet 120 is disposed below the 200.

The lamp 110 is disposed at one side of the light guide plate 200. The lamp 110 generates light in response to a power applied from an external inverter (not shown). The lamp 110 is, for example, made of a cold Cathode Fluorescent Lamp (CCFL) having an elongated cylindrical shape. In contrast, the lamp 110 may be formed of an external electrode fluorescent lamp (EEFL) having electrodes formed on outer surfaces of both ends.

Although not shown, the backlight assembly 100 may further include a lamp cover that covers the three surfaces of the lamp 110 and protects the lamp 110. The lamp cover is made of a material having a high reflectance, or has a structure coated with a reflective material having a high reflectance on an inner surface thereof, and reflects light generated from the lamp 110 to the light guide plate 200 to improve light utilization efficiency.

The light guide plate 200 guides a traveling path of light incident from the lamp 110. The light guide plate 200 is made of a transparent material for guiding light. For example, the light guide plate 200 is made of polymethyl methacrylate (PMMA).

The light guide plate 200 includes a light receiving part 210, a light receiving part 220, an emission part 230, and a reflecting part 240. The light generated from the lamp 110 is incident into the light guide plate 200 through the light incident part 210. The light receiving unit 220 faces the light receiving unit 210 and has a thickness thinner than that of the light receiving unit 210. The exit unit 230 extends vertically from the top side of the light incident unit 210 and is connected to the top side of the light projecting unit 220. The reflective part 240 extends from the lower side of the light incident part 210 and is connected to the lower side of the light receiving part 220. Therefore, the light guide plate 200 has a wedge shape in which the thickness becomes thinner from the light incidence portion 210 toward the light portion 220 side.

A plurality of first prism patterns 250 are formed in the reflector 240 of the light guide plate 200. As illustrated in FIG. 3, the first prism patterns 250 have a stripe shape formed in parallel with the light incident part 210. That is, the first prism patterns 250 are formed in a direction parallel to the length direction of the lamp 110. In addition, the first prism patterns 250 are formed at regular intervals.

The region of the reflector 240 positioned between the first prism patterns 250 is formed in parallel with the emission unit 230 such that the light guided into the light guide plate 200 always satisfies the total reflection condition. That is, the region of the reflector 240 positioned between the first prism patterns 250 is formed perpendicular to the light incident part 210.

Therefore, the light incident through the light incident part 210 into the light guide plate 200 is totally reflected through the reflecting part 240 and the exiting part 230, and the reflection angle is changed by the first prism pattern 250. It is emitted vertically through 230.

Meanwhile, the first prism patterns 250 may be formed on the reflector 240 by various methods such as an injection method and a stamping method.

The reflective sheet 120 is disposed on the reflecting part 240 side of the light guide plate 200. The reflective sheet 120 reflects light leaking to the outside through the reflecting unit 240 of the light guide plate 200 and enters the light into the light guide plate 200 again. The reflective sheet 120 is made of a material having high light reflectance. For example, the reflective sheet 120 is made of white polyethylene terephthalate (PET) material, white polycarbonate (PC) material, or the like.

4 is an enlarged view illustrating an enlarged portion A of FIG. 2.

Referring to FIG. 4, the first prism patterns 250 are formed at regular intervals on the reflecting part 240 of the light guide plate 200, and the reflecting part 240 areas are disposed between the first prism patterns 250. Is formed in parallel with the exit unit 230.

The light incident from the lamp 110 to the light guide plate 200 through the light incidence unit 210 is within the range of not exceeding a specific critical angle α with respect to the normal line NL of the light incidence unit 210. It goes inside. The critical angle α represents a maximum angle that may be formed based on the normal NL of the light incident part 210 when the light incident on the light incident part 210 proceeds to the inside of the light guide plate 200.

The critical angle [alpha] can be obtained from Equation 1 below showing Snell's law.

n ₁ × sinθ ₁ = n ₂ × sinθ ₂

Where n ₁ is the refractive index of the first medium and n ₂ is the refractive index of the second medium. Further, θ ₁ is an angle formed by the normal of the incident surface and the light in the first medium, and θ ₂ is an angle formed by the normal of the incident surface and the light in the second medium.

Assuming that the second medium is a denser medium than the first medium, the refractive index n ₂ of the second medium is greater than the refractive index n ₁ of the first medium. Therefore, in order to satisfy the equation 1, θ2 is smaller than θ1.

Accordingly, when light travels from the first medium, which is a small medium, to the second medium, which is a dense medium, the value of θ2 also increases as the value of θ1 increases, and the corresponding θ2 when the value of θ1 is 90 °. The value becomes the critical angle α. Therefore, the critical angle α is expressed by Equation 2 below.

α = sin ^-1 (n ₁ / n ₂ )

Thus, the critical angle α is determined by the refractive indices of the first medium and the second medium.

In the present embodiment, the first medium is air existing between the lamp 110 and the light guide plate 200, and the second medium is the light guide plate 200. The refractive index of air is one. When the light guide plate 200 is, for example, polymethyl methacrylate (hereinafter referred to as PMMA), the refractive index is 1.49. Thus, for the PMMA light guide plate, the critical angle α is about 42.16 degrees.

Meanwhile, the light reaching the light incident part 210 of the light guide plate 200 from the lamp 110 proceeds to the inside of the light guide plate 200 within a critical angle α. Light introduced into the light guide plate 200 reaches the reflector 240 or the emitter 230. At this time, the light that satisfies the total reflection condition of the light guide plate 200 among the light reaching the reflector 240 or the emitter 230 is reflected back into the light guide plate 200, but the light that does not satisfy the total reflection condition is light guide plate ( 200 is emitted outside.

That is, among the lights reaching the reflector 240 or the emitter 230, the light reaching at an angle greater than the threshold angle α based on the normal of the emitter 230 is returned to the inside of the light guide plate 200. Although reflected, the light reaching at an angle smaller than the critical angle α is emitted to the outside of the light guide plate 200.

In the present exemplary embodiment, the region of the reflector 240 positioned between the first prism patterns 250 is formed to be parallel to the emission unit 230, and thus, based on the normal NL of the light incident unit 210, The light reached at an angle below the critical angle α is totally reflected. On the other hand, some of the light that reaches the reflector 240 is changed by the first prism patterns 250, the traveling angle is changed, and below the critical angle (α) based on the normal of the dual emission unit 230 The light reaching the exit unit 230 at an angle exits to the outside.

Accordingly, the light introduced into the light guide plate 200 through the light incidence unit 210 is totally reflected through the region of the reflector 240 positioned between the emission unit 230 and the first prism patterns 250, and then the first prism. The reflection angle is changed by the pattern 250 and is emitted through the emission unit 230.

5 is an enlarged view illustrating an enlarged portion B of FIG. 4.

Referring to FIG. 5, the first prism pattern 250 formed on the reflecting part 240 of the light guide plate 200 has a triangular cross-section basically to emit light traveling in the light guide plate 200 in a vertical direction. Having a groove.

The first prism pattern 250 includes a first inclined surface 252, a second inclined surface 254 connected to the first inclined surface 252, and a third inclined surface 256 connected to the second inclined surface 254.

The first inclined surface 252 is formed to be inclined from the reflecting part 240 toward the exit part 250. The second inclined surface 254 is formed to be inclined in the direction of the reflector 240 from the first inclined surface 252. The third inclined surface 256 extends in parallel with the first inclined surface 252 from the second inclined surface 254 and is connected to the reflector 240.

The first inclined surface 252 and the second inclined surface 254 have a substantially symmetrical structure with respect to the normal of the exit portion 230.

In the present exemplary embodiment, the light guide plate 200 has a first thickness d1 at the light incident part 210, a second thickness d2 thinner than the first thickness d1 at the light receiving part 220, and a first thickness d1. The region of the reflector 240 positioned between the prism patterns 250 has a structure parallel to the emission unit 230. Therefore, the thickness difference between the previous stage and the subsequent stage is generated based on the first prism pattern 250.

The first height h1 of the third inclined surface 256 corresponding to the difference in thickness between the front end and the rear end of the first prism pattern 250 may be obtained by the following equation (3).

(d1-d2) / m

Here, d1 is the first thickness of the light incident part 210, d2 is the second thickness of the light incident part 220, and m is the number of steps of the reflector 240.

That is, the first height h1 of the third inclined surface 256 is determined according to the thickness difference between the light incident portion 210 and the light facing portion 220 and the number of steps of the reflecting portion 240.

On the other hand, the second height h2 of the first inclined surface 252, the first bottom side b1 of the third inclined surface 256, the second bottom side b2 of the second inclined surface 254, and the like are guided into the light guide plate 200. The guided light is optimized so that no lost light is generated by side emission.

The second height h2 of the first inclined surface 252 preferably has a height at which light propagating below the critical angle α does not reach the third inclined surface 256 based on the normal of the light incident part 210. . Therefore, the second height h2 of the first inclined surface 252 can be obtained by the following equation (4).

h1 × [1 + tan (α) tan (β / 2)] / [1-tan (α) tan (β / 2)]

Here, α is a critical angle of the light guide plate 200, and β is an internal angle formed by the first inclined surface 252 and the second inclined surface 254.

In addition, the first base b1 of the third inclined surface 256 may be obtained by the following equation (5).

h1 × tan (β / 2)

In addition, the second base b2 of the second inclined surface 254 may be obtained by the following equation (6).

h2 × tan (β / 2)

Meanwhile, in order to emit light guided into the light guide plate 200 in the vertical direction, the inner angle β formed by the first inclined surface 252 and the second inclined surface 254 has a range of about 60 ° to about 90 °. Preferably, the inner angle β formed by the first inclined surface 252 and the second inclined surface 254 is about 78 °.

In the case of the PMMA light guide plate which is most often used as the light guide plate 200, it has a critical angle α of about 42.16 °. For example, when the length from the light incidence portion 210 to the light portion 220 of the PMMA light guide plate is about 213 mm, and the pitch between the first prism patterns 250 is about 300 μm, the step of the reflector 240 is performed. The number is 710.

At this time, when the first thickness d1 of the light incident part 210 of the PMMA light guide plate is about 2.6 mm, and the second thickness d2 of the light guide part 220 is about 0.7 mm, the thickness difference is about 1.9 mm. Therefore, according to Equation 3, the first height h1 of the third inclined surface 256 is about 2.68 μm.

At this time, when the inner angle β between the first inclined surface 252 and the second inclined surface 254 is formed at about 78 °, the second height h2 of the first inclined surface 252 is about 17.38 by Equation 4. Μm, and the first base b1 of the third inclined plane 256 is about 2.17 μm by Equation 5, and the second base b2 of the second inclined plane 254 is about 14.07 by Equation 6. It becomes micrometer.

FIG. 6 is a plan view illustrating another embodiment of the first prism patterns illustrated in FIG. 3.

Referring to FIG. 6, a plurality of first prism patterns 260 are formed in the reflector 240 of the light guide plate 200. The first prism patterns 260 have a stripe shape formed in parallel with the light incident part 210. That is, the first prism patterns 260 are formed in a direction parallel to the longitudinal direction of the lamp 110.

In the present embodiment, the first prism patterns 260 are formed to be narrower as the distance from the light incident portion 210 where the lamp 110 is disposed, that is, toward the light facing portion 220.

As such, by adjusting the pitch between the first prism patterns 260, the uniformity of light may be improved.

Meanwhile, since the shapes of the first prism patterns 260 are the same as those shown in FIGS. 4 and 5, detailed descriptions thereof will be omitted.

FIG. 7 is a plan view illustrating still another embodiment of the first prism patterns illustrated in FIG. 3.

Referring to FIG. 7, a plurality of first prism patterns 270 are formed in the reflector 240 of the light guide plate 200. The first prism patterns 270 have a stripe shape formed in parallel with the light incident part 210. That is, the first prism patterns 270 are formed in a direction parallel to the longitudinal direction of the lamp 110.

In this embodiment, each first prism pattern 270 is formed to be broken at predetermined intervals to adjust the uniformity of light. The broken regions of the first prism patterns 270 may be the same or different regions with respect to all the first prism patterns 270. In addition, the first prism patterns 270 may be formed at equal intervals, or may be narrower as they move away from the light incident part 210.

Meanwhile, since the shapes of the first prism patterns 260 are the same as those shown in FIGS. 4 and 5, detailed descriptions thereof will be omitted.

8 is a perspective view illustrating a light guide plate according to another exemplary embodiment of the present invention, and FIG. 9 is an enlarged view illustrating a portion C of FIG. 8.

8 and 9, the light guide plate 300 according to another embodiment of the present invention faces the light incident part 310 and the light incident part 310 to which light from the lamp 110 is incident. ) Extending from the lower side of the light exiting unit 330 and the light exiting unit 310 extending vertically from the upper side of the light incident unit 310 to be connected to the upper side of the light incident unit 320. And a reflecting unit 340 connected to the lower side of the light unit 320. Therefore, the light guide plate 300 has a wedge shape in which the thickness becomes thinner from the light incident part 310 toward the light guide part 320.

The first prism pattern 350 having a stripe shape formed in parallel with the light incident part 310 is formed in the reflective part 340 of the light guide plate 300. In addition, the region of the reflector 340 positioned between the first prism patterns 350 is formed in parallel with the emission part 330 such that the light guided into the light guide plate 300 always satisfies the total reflection condition.

Therefore, the light introduced into the light guide plate 300 through the light incident part 310 is totally reflected through the reflecting part 340 and the exiting part 330, and the reflection angle of the light is changed by the first prism patterns 350. Vertical exit through the unit 330.

Since the first prism patterns 350 have been described with reference to FIGS. 3 and 7, detailed description thereof will be omitted.

In the present embodiment, a plurality of second prism patterns 360 are formed in the exit part 330 of the light guide plate 300. The second prism patterns 360 are formed over the entire surface of the emission unit 330, and focus the traveling direction of the light emitted through the emission unit 330 in the front direction to improve front luminance.

The second prism patterns 360 are formed in a direction perpendicular to the longitudinal direction of the lamp 110, that is, in a direction perpendicular to the light incident part 310. Therefore, the first prism patterns 350 and the second prism patterns 360 are formed in a direction perpendicular to each other.

The second prism patterns 360 have a substantially triangular cross section perpendicular to the length direction. The pitch P between the second prism patterns 360 has a range of about 50 μm to about 150 μm, and the vertex angle θ of the second prism patterns 360 has a range of about 60 ° to about 120 °. .

Meanwhile, an upper end of the second prism patterns 360, that is, an edge portion where two inclined surfaces meet may have a rounded shape. In contrast, the second prism patterns 360 may have a substantially semi-elliptic or semi-circular cross section perpendicular to the length direction.

10 is an exploded perspective view illustrating a liquid crystal display according to an exemplary embodiment of the present invention.

Referring to FIG. 10, the liquid crystal display device 400 according to an exemplary embodiment may include a backlight unit 100 for supplying light and a display unit for displaying an image using light supplied from the backlight assembly 100. 500).

The backlight assembly 100 includes a lamp 110 for generating light, a light guide plate 200 for guiding a path of light generated from the lamp 110, and a reflective sheet 120 disposed under the light guide plate 200. In the present embodiment, the backlight assembly 100 may have any one of several embodiments shown in FIGS. 1 to 9. Therefore, the same reference numerals are used for the same components, and detailed description thereof will be omitted.

The display unit 500 includes a liquid crystal display panel 510 for displaying an image using light supplied from the backlight assembly 100, and a driving circuit unit 520 for driving the liquid crystal display panel 510.

The liquid crystal display panel 510 includes a first substrate 512, a second substrate 514 coupled to the first substrate 512, and a liquid crystal interposed between the first substrate 512 and the second substrate 514. Layer (not shown).

The first substrate 512 is a TFT substrate in which thin film transistors (hereinafter referred to as TFTs) as switching elements are formed in a matrix form. For example, the first substrate 512 is made of a transparent glass material for light transmission. A data line and a gate line are respectively connected to the source terminal and the gate terminal of the TFTs, and a pixel electrode made of a transparent conductive material is connected to the drain terminal.

The second substrate 514 is a color filter substrate in which RGB pixels for realizing color are formed in a thin film form. For example, the second substrate 514 is made of a transparent glass material. The common electrode made of a transparent conductive material is formed on the second substrate 514.

In the liquid crystal display panel 510 having such a configuration, when power is applied to the gate terminal of the TFT and the TFT is turned on, an electric field is formed between the pixel electrode and the common electrode. By the electric field, the arrangement of liquid crystal molecules of the liquid crystal layer interposed between the first substrate 512 and the second substrate 514 is changed, and the transmittance of light supplied from the backlight assembly 100 is changed according to the arrangement change of the liquid crystal molecules. The image is changed to display an image of a desired gradation.

The driving circuit unit 520 may include a data printed circuit board 521 for supplying a data driving signal to the liquid crystal display panel 510, a gate printed circuit board 522 for supplying a gate driving signal to the liquid crystal display panel 510, and data printing. It includes a data driving circuit film 523 connecting the circuit board 521 to the liquid crystal display panel 510 and a gate driving circuit film 524 connecting the gate printed circuit board 523 to the liquid crystal display panel 510. do.

The data driving circuit film 523 and the gate driving circuit film 524 include a data driving chip 525 and a gate driving chip 526. The data driving circuit film 523 and the gate driving circuit film 524 are made of, for example, a tape carrier package (TCP) or a chip on film (COF).

Meanwhile, the gate printed circuit board 522 may be removed by forming separate signal lines on the liquid crystal display panel 510 and the gate driving circuit film 524.

The liquid crystal display device 400 may further include at least one optical sheet 410 disposed between the backlight assembly 100 and the liquid crystal display panel 510.

The optical sheet 410 improves brightness characteristics of light emitted from the light guide plate 200. The optical sheet 410 may include a diffusion sheet for diffusing the light emitted from the light guide plate 200 to improve luminance uniformity. In addition, the optical sheet 410 may include a prism sheet for condensing the light emitted from the light guide plate 200 in the front direction to improve the front brightness of the light. In addition, the optical sheet 410 may include a reflective polarizing sheet for increasing the brightness of the light in a manner that transmits light that satisfies a specific condition and reflects the remaining light. Meanwhile, the optical sheet having various functions may be added or removed in the liquid crystal display device 400 according to required luminance characteristics.

According to the backlight assembly and the liquid crystal display having the same, the light guided into the light guide plate in the wedge-shaped light guide plate structure is vertically emitted by the prism patterns formed in the reflecting portion, and totally reflected between the prism patterns. Therefore, the lost light emitted to the side of the light guide plate can be reduced, and the brightness of the light emitted to the emitting portion can be increased.

In addition, by forming the prism patterns in the exit portion of the light guide plate, it is possible to further increase the front luminance of the emitted light.

In the detailed description of the present invention described above with reference to the preferred embodiments of the present invention, those skilled in the art or those skilled in the art having ordinary skill in the art will be described in the claims to be described later It will be understood that various modifications and variations can be made in the present invention without departing from the scope of the present invention.

Claims (21)

 A light incident part to which light from the lamp is incident; A light facing portion facing the light incident portion and having a thickness thinner than the light incident portion; An emission unit extending vertically from an upper side of the light incident unit and connected to an upper side of the light receiving unit; And A reflection part extending from a lower side of the light incident part and connected to a lower side of the light incident part, A plurality of first prism patterns are formed in the reflective part, and the light guide plate is formed between the first prism patterns in parallel with the emission part. The light guide plate of claim 1, wherein the first prism patterns have a stripe shape formed in parallel with the light incident part. 3. The method of claim 2, wherein each of said first prism patterns is A first inclined surface formed to be inclined from the reflecting part toward the emitting part; A second inclined surface formed to be inclined from the first inclined surface toward the reflecting part; And And a third inclined surface extending in parallel with the first inclined surface from the second inclined surface and connected to the reflecting portion. The light guide plate according to claim 3, wherein the first inclined surface and the second inclined surface have a substantially symmetrical structure with respect to the normal of the exit portion. The method of claim 4, wherein the first height h1 of the third inclined surface is (d1-d2) / m The light guide plate which is characterized by the above-mentioned. Here, d1 is the first thickness of the light incident portion, d2 is the second thickness of the light incident portion, and m is the number of steps of the reflecting portion. The method of claim 5, wherein the second height h2 of the first inclined surface is h1 × [1 + tan (α) tan (β / 2)] / [1-tan (α) tan (β / 2)] The light guide plate which is characterized by the above-mentioned. (Where α is sin ⁻¹ (n ₁ / n ₂ ) and β is an internal angle formed by the first inclined plane and the second inclined plane, where n ₁ is a refractive index of a medium disposed between the lamp and the light incident portion , n ₂ is the refractive index of the light guide plate.) The method of claim 6, The first base b1 of the third inclined surface is h1 × tan (β / 2), The second bottom side b2 of the second inclined surface is h2 × tan (β / 2). The light guide plate according to claim 7, wherein an inner angle β formed by the first inclined plane and the second inclined plane is 60 ° to 90 °. The light guide plate of claim 2, wherein each of the first prism patterns is formed to be broken at predetermined intervals. The light guide plate of claim 2, wherein the first prism patterns are formed at equal intervals. 3. The light guide plate of claim 2, wherein the first prism patterns are narrower in distance from the light incident part. The light guide plate of claim 1, wherein a plurality of second prism patterns are formed in the exit part. The light guide plate of claim 12, wherein the second prism patterns are formed in a direction perpendicular to the light incident part. A light incident part to which light from the lamp is incident; A light facing portion facing the light incident portion and having a thickness thinner than the light incident portion; An emission unit extending vertically from an upper side of the light incident unit and connected to an upper side of the light receiving unit; And A reflection part extending from a lower side of the light incident part and connected to a lower side of the light incident part, A plurality of first prism patterns having a stripe shape parallel to the light incident part is formed in the reflective part, and the first prism patterns are formed in parallel with the emission part. The light guide plate, characterized in that a plurality of second prism patterns are formed in the exit portion in a direction perpendicular to the light incident portion. A lamp for generating light; A light guide plate guiding a path of light generated from the lamp; And It includes a reflective sheet disposed below the light guide plate, The light guide plate is A light incident part to which light from the lamp is incident, A light facing portion facing the light incident portion and having a thickness thinner than that of the light incident portion, An emission unit extending vertically from an upper side of the light incident unit and connected to an upper side of the light receiving unit; A reflection part extending from a lower side of the light incident part and connected to a lower side of the light incident part, A plurality of first prism patterns are formed in the reflecting portion, the backlight assembly, characterized in that formed between the first prism patterns in parallel with the emitting portion. The backlight assembly of claim 15, wherein the first prism patterns have a stripe shape formed in parallel with the light incident portion. The method of claim 16, wherein each of the first prism pattern is A first inclined surface formed to be inclined from the reflecting part toward the emitting part; A second inclined surface connected to the first inclined surface and having a symmetrical structure with the first inclined surface with respect to a normal line of the emission part; And And a third inclined surface extending in parallel with the first inclined surface from the second inclined surface and connected to the reflecting portion. The backlight assembly of claim 16, wherein the emission part has a plurality of second prism patterns formed in a direction perpendicular to the light incident part. A backlight assembly including a lamp for generating light, a light guide plate for guiding a path of light generated from the lamp, and a reflective sheet disposed below the light guide plate; And A display unit having a liquid crystal display panel for displaying an image using light from the backlight assembly and a driving circuit unit for driving the liquid crystal display panel; The light guide plate is A light incident part to which light from the lamp is incident, A light facing portion facing the light incident portion and having a thickness thinner than that of the light incident portion, An output unit extending vertically from an upper side of the light incident unit and connected to an upper side of the light receiving unit; A reflection part extending from a lower side of the light incident part and connected to a lower side of the light incident part, A plurality of first prism patterns are formed in the reflecting portion, wherein the first prism patterns are formed in parallel with the exit portion. The liquid crystal display device of claim 19, wherein the first prism patterns have a stripe shape formed in parallel with the light incident portion. 21. The liquid crystal display of claim 20, wherein a plurality of second prism patterns are formed in the light exit part in a direction perpendicular to the light exit part.

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